Detector carriage for examining submerged surface of ship's hull - uses follower carriage moving along reference line for accurate location of position

摘要

The technique for checking the underside of the ship's hull includes the use of a self-propelled carriage which carries a detector across the submerged surface of the ship's hull. A follower carriage is arranged to move along the length of the ship on a chosen reference line, and its position is determined along this line. The lateral position of the detector relative to the follower carriage is determined ultrasonically. Thus a coordinate location is identified for the position at which the detector is operating.